Click on map to open large map in new window (Map updated: 11 August 2009)

Click here to view an interactive map of the Northern Ireland dataset as currently collated by CEDaR.The map is generated through the NBN Gateway using their Interactive Mapping Tool.

This lichen is common on acid-barked trees, rocks, wood and soil where the effect of nutrient enrichment is generally absent. The thallus consists of a spreading crust of tiny, olive green warts named goniocysts. It is frequently with discs, but these are mostly very small. They vary from pinkish-beige, through darker-brown to black. A beginner may be tricked into believing this is an algal crust. Trees that should be examined for it include alder and birch, especially in the more remote areas of Ireland.

Key characteristics

The scurfy, rather dark, grey to olive green, granule-woven thallus with small discs of a variety of colours generally indicates this species

It is now known to be a member of an aggregate and separation into the various species of the aggregate is a task for experts.